Sorry to say, but you definitely made yourself sound like an ass there.
He's a druid, not one of the plate-wearing tanks. Aside from maybe trinkets, there is no "tank gear" for bear druids... the idea of having tank-specific leather gear was scrapped with WotLK. So, aside from being a little lacking on hit/crit/mastery, pvp gear is just fine for bear tanking... in fact, it might even be a bit preferred in certain cases, as pvp gear is generally tilted a bit towards having more stamina.
In the future, I'd suggest actually learning about a class before you criticize someone about it.